Climate change, impacts and vulnerability in Europe ... - MemoFin.fr

Climate impacts on environmental systems3.5.3 Soil erosionRelevanceSoil erosion by water has substantial on-site as wellas off-site effects. By removing fertile topsoil, erosionreduces soil productivity and, where soils areshallow, may lead to the loss of the entire soil body.Soil removed by run-off, for example during a largestorm, will create mudflows that will accumulatebelow the eroded areas, in severe cases blockingroadways or drainage channels and inundatingbuildings. Erosion can lead to restrictions on landuse and land value, damage to infrastructure,pollution of water bodies, and negative effects onhabitats and biodiversity.Based on potential loss of wheat yields, aconservative estimate of the consequence of erosionby water for the EU-27 (excluding Greece, Cyprusand Malta), reveals that agricultural productionequivalent to a value of EUR 3.5 billion could beunder threat. If the economic loss of soil carbonis also added, the figure would be even higher. In2011, the removal of topsoil by strong winds afterploughing in very dry conditions in Germanycaused a traffic accident that killed 10 people andinjured at least 100 others; this is an indirect effect ofwind erosion (see Section 4.6).Climate change will influence soil erosion processes,mainly triggered by extreme rainfall events anddroughts. Excess water due to intense or prolongedprecipitation can cause tremendous damage tosoil through sheet wash, gully erosion and evenlandslides. However, if soils are managed well,resistance to erosion by water and/or wind can beimproved considerably.Past trendsSystematic and harmonised data on trends insoil erosion across Europe are lacking. EU-wideestimates of erosion are based on modellingstudies, most of which have not yet been validated.A recent exercise has estimated that the surfacearea in the EU‐27 (excluding Greece, Cyprus andMalta ( 54 )) affected by water erosion is 130 millionha. Almost 20 % is subjected to soil loss in excessof 10 tonnes/ha/year (Bosco et al., forthcoming;Jones et al., 2012) (Map 3.21). Most models containa rainfall erosivity factor and a soil erodibilityfactor that reflect average precipitation conditions.Typical values for these factors may inadequatelyrepresent the impact of extreme rainfall. Therefore,the uncertainty of modelled erosion risk is high,especially at local level.The situation for wind erosion is similar to erosionby water in that systematic data collections arelimited. Wind erosion is estimated to be a seriousproblem in many parts of eastern England,north‐west France, northern Germany, parts ofthe Iberian Peninsula and eastern Netherlands(Map 3.22).Key messages: 3.5.3 Soil erosion• 105 million ha, or 16 % of Europe's total land area (excluding Russia) were estimated to be affected bywater erosion in the 1990s.• Some 42 million ha. of land were estimated to be affected by wind erosion, of which around 1 millionha. were categorised as being severely affected.• A recent new model of soil erosion by water has estimated the surface area affected in the EU-27 at130 million ha. Almost 20 % is subjected to soil loss in excess of 10 tonnes/ha/year.• Increased variations in rainfall pattern and intensity will make soils more susceptible to water erosion,with off-site effects of soil erosion increasing.• Increased aridity will make finer-textured soils more vulnerable to wind erosion, especially ifaccompanied by a decrease in soil organic matter levels.• Reliable quantitative projections for soil erosion are not available( 54 ) Lacking Corine Land Cover data for 2006.Climate change, impacts and vulnerability in Europe 2012151